The Long-tailed Tit (Aegithalos caudatus), is a very small passerine bird. It breeds in most of Europe and Asia. It is usually a non-migratory species, although there have been several extralimital records, and migration has been observed in north-eastern Europe.In the winter it is often found with tit flocks.
This is a very small bird at only 13–15 cm in length including its very long tail, which makes up 7–9 cm of the total. The Long-tailed Tit is black and brown above and whitish below, with reddish flanks. It has a white crown. North European birds (A. c. caudatus) have completely white heads and flanks. There are several other subspecies which vary substantially in plumage (such as European birds have got black above eye and Turkish birds has got greyish "eyebrow" above eye and black thoat with grey scapulars). Hybridization between subspecies is common, and the hybridization zone between caudatus and europaeus seems to move in an easterly direction.
Long-tailed Tits are found in deciduous woodlands with significant undergrowth. This is a restless species, constantly on the move as it searches for insects and other small food items. During the autumn and winter, it is usually found in flocks of up to thirty individuals; it has been described as an avian sheep. During the breeding season (late February to July), Long-tailed Tits form monogamous pairs, and raise a single brood of six to twelve eggs in a woven closed nest, often concealed within a tree or shrub. The nest is held together with spider webs, camouflaged with lichen and lined with feathers. Adult male birds will often choose to assist their parents or brothers in raising offspring if their own nest is predated.
The two main calls are a srih-srih-srih, and a churr.